Spatio-temporal variation in wave power and implications for electricity supply

I Fairley,H.C.M Smith,B Robertson,M Abusara,I Masters

doi:10.1016/j.renene.2017.03.075

Abstract

Wave energy resources are intermittent and variable over both spatial and temporal scales. This is of concern when considering the supply of power to the electricity grid. This paper investigates whether deploying arrays of devices across multiple spatially separated sites can reduce intermittency of supply and step changes in generated power, thereby smoothing the contribution of wave energy to power supply. The primary focus is on the southwest UK; SWAN wave model hindcast data are analysed to assess the correlation of the resource across multiple sites and the variability of power levels with wave directionality. Power matrices are used to calculate step changes in the generated power with increasing numbers of sites. This is extended to national and European scales using ECMWF hindcast data to analyse the impacts of generating power at multiple sites over wider areas. Results show that at all scales the step change in generated power and the percentage of time with zero generation decreases with increasing numbers of sites before plateauing. This has positive implications for performance of electricity grids with high levels of renewable penetration.

Highlights

Concerns are often raised over intermittency of electricity generation from renewable sources and associated cost implications as the market share of renewable energy increases [2,13,22]
Point 1 in South Cornwall and the point at the Low Carbon Research Institute (LCRI) site have the majority of waves approaching form the south west while the point at Wave Hub and output location 9 have waves most commonly incident from the west, reflecting their locations and local geography
One of the aims of this study is to investigate how power levels vary with differing wave direction around the coastline

Summary

Introduction

Concerns are often raised over intermittency of electricity generation from renewable sources and associated cost implications as the market share of renewable energy increases [2,13,22]. Depending on the penetration level of renewable generation, intermittency can create problems for grid management [19,35]. High levels of flexible balancing plants are required and availability of balancing plants limits the amount of intermittent power that can be integrated into the grid. In the form of wave and tidal stream, is a relative newcomer to the field of renewable electricity generation. Tidal energy is highly predictable, with spatially phased cyclical intermittency driven by the relative motions of the Earth, Moon and Sun. Studies have investigated the potential reduced intermittency in generated power due to out of phase energy extraction sites around the Northwest European shelf [34,38]. As technology develops and allows exploitation of lower energy sites, phase differences between second generation lower flow sites may be more beneficial [39]

Objectives

Results

Discussion

Conclusion